A refuelling probe was in the original spec but was subsequently deemed un-necessary by the powers that be.
I think that another Black Buck would be quite possible.
In a deployment mission, the A330 MRTT enables four Eurofighters, to fly 3,600 nm by refuelling them en-route, or, when carrying 20 tonnes of payload, to fly these four fighters a distance of 2,800 nm.
The A330 MRTT can also be used on towline mission, whereby it can be on station at about 1,000 nm from its base for some 4 hours 30 minutes, with the capability to provide 50 tonnes of fuel for needing receivers. Or to provide 60 tonnes of fuel while remaining on station for 5 hours at 500 nm from base. This exceeds by far what any other current tanker can offer
A330 MRTT